Lack of oxygen isn't what limits human tissue regeneration. Unless of course if we talk about, say, pressure ulcers or other such conditions where lack of circulation and oxygen supply is the limiting factor. But the fact that we cannot regenerate a new hand or an eye is not because there'd be too little oxygen available.

One of my profs is researching the use of stem cells and regeneration and she basically said that the mechanism we evolved to heal and create scar tissue is what prevents us from regenerating limbs. Evolutionarily, it's more important to stop a large bleed than to actually grow one back. Supposedly if we knew what cocktail of cytokines to use, we'd just pour(in a highly sophisticated manner) some on an open wound and the cells would know what to do.

Living one day at a time; Enjoying one moment at a time; Accepting hardships as the pathway to peace; ~Niebuhr

SO what if since as long as we have dependable historical records people had already messed something up physically or environmentally that made it hard to regenerate limbs?Haha, that would be amazing...

Why not sequence the axolotl, the starfish and others, and compare it to our own? There is definitely merit in examining oxygen intake. Ologists of some sort measured the oxygen level in a bubble encased in amber and found it to be around 31-38%. I was taught in school that O2 was at 21%. Current measurements show it at 17% One scientist claims that 12% is fatal. Don't know where I'm going with this. Just thought I'd regurgitate, I guess. Anyway, we are holographic in the sense that every cell contains the entire DNA sequence, so it seems that we are most likely capable of regeneration. It's quite possible that our environmental history (thousands? millions of years?) prevents it. Or maybe it's not intended that we do. Population control would be a bitch!

Part of the reason those creatures can regenerate is because of the simplicity of their structure, we are much larger and have many different cell types when it comes to regeneration, evolutionarily speaking the humans who have better repair systems should have increased in frequency and we are the result. If we were able to undergo rapid regeneration the trade off might have been our complexity or other characteristics that increase our fitness in the environment.

I think regeneration is a very helpful thing to many people as it gives us the ability to be complex and to repair damage to that system.

Jesse

I spit in the mouth of a god, who whispers in the minds of the children

"The most incomprehensible thing about the universe is that it is at all comprehensible" - Albert Einstein.

Epimorphic regeneration should be available to any organism, simple or complex. It should just be a recapitulation of the developmental genetic program. Now, there can be a hinderance to accessing the develpmental genetic program, but there should be ways around that. Like how to block fibrosis (scar tissue formation) and proceed to epithelial cells disengaging from the basement membrane and sliding over the wound opening. Dedifferentiation of local cells to form the structure, and then transdifferentiation of the cells following the developmental genetic program and renewing the limb/organ. Cell signaling may be the key to unlocking this mystery.

And then once this mystery is unlocked and mastered, then we can begin the enhancements (for example Wolverine).

While researching regeneration (again), I came across regulatory proteins that are found in oncogenes and for the cell cycle. I wonder if cancer is our mutation towards regeneration, except that we haven't found the right regulatory proteins to make it work viably yet.

I think cancer is more like a blast from the past - cancer cells resemble unicellular organisms in that they do not see "the big picture" but instead just multiply time after time as long as there are nutrients available, even if it meant their own demise as well.

Regulatory proteins we have have evolved in part to prevent this in order to make us function as a whole, not as individual cells.

I find it highly unlikely that we are evolving anywehre towards the ability to regenerate any better than we do now - because as it can clearly be seen, the more "advanced" an organism is, the poorer its regenerative capabilities are.

Like it has already bee sain in this thread, in bigger animals and especially in warm-blooded ones, there is much more acute need to stop bleeding and create scar tissue to block the wound rather than trying to grow back a limb.

I believe it would be an extremely challenging task to artificially create an environment where humans could regenerate back a limb, with all the issues of genetic regulation and cytokine/hormone environment that is reguired for it to happen properly.